(a) Field of the Invention
The present invention relates to a bicycle saddle adjustment structure, more particularly a bicycle saddle adjustment structure installed above the seat post of a bicycle.
(b) Description of the Prior Art
The conventional bicycle saddle adjustment structure is based on two clamps mounted above the seat post and secured by bolts to a pair of rails underneath the saddle. The design involves a complicated process of saddle assembly and adjustment, which lowers efficiency in racing and in mass production. As a result, some manufacturers attempt to improve the saddle adjustment structure. One of such attempts is the U.S. Pat. No. 4,783,119 "Lightweight Adjustable Bicycle Saddlemount" which describes installing a crosspin (25) suitably on the post (1). On top of the post is a recess (6) for accommodating a semispool (3). The semispool (3) and a pair of clamps (4) mounted on it are used to secure the two rails (18) under the saddle. Two bolts (5) are threaded through the lower part of holes (9) at the front and rear parts of the crosspin (25) to the female thread (20) of the two clamps (4). This design provides spherical contact between the central core (12) of the semispool (3) and the recess (6) to enable for-and-aft saddle adjustment. However, the angular adjustment is restricted by the confinement of the two bolts (5) in the holes (9). Only a small adjustment is allowed. If the holes (9) are too big, the semispool (3) would be loose. If the holes (9) are too small, it will be almost impossible to adjust the angle. As a result, the patent is very inconvenient in application. Furthermore, completion of the saddle assembly or adjustment must rely on turning, adjusting and screwing the two bolts (5) threaded through the holes (9) at the front and rear parts of the crosspin (25), which is very time consuming. Besides, when the saddle has to be adjusted, the two bolts (5) cannot restrain each other because the two clamps (4) on the semispool ( 3) are separated into front and back parts. Therefore, it is difficult to adjust the bolts (5) to exert parallel forces to the front and rear parts of the semispool (3). Saddle adjustment is therefore very inconvenient.